1. Field of the Invention
This invention relates to an apparatus and method for monitoring cleaning processes for medical devices. More particularly, this invention relates to an apparatus and method capable of determining when the device is sufficiently cleaned so that the device can be sterilized.
2. Description of the Related Art
Adequate cleaning of contaminated medical instruments and devices is essential for safe disinfection and sterilization. Failure to adequately remove inorganic and organic soil derived from body liquids and tissues can impede the effectiveness of subsequent sterilization procedures resulting in infections. Additionally, remaining foreign materials introduced during subsequent invasive procedures can produce pyrogenic reactions that can impede healing.
It is preferable to use machine processes for cleaning which have been validated for this purpose in a clinical setting and which preferably accomplish sterilization during or after the cleaning cycle. The selected cleaning processes should produce satisfactory results under certain test and field conditions as well as ensure that adequate cleaning is performed under exceptional circumstances and conditions.
It is not only necessary that a high level of cleaning performance be achieved, but also that the cleaning system be capable of adapting to the specific needs of particular medical instruments and devices. The ideal cleaning system will be capable of adequately cleaning medical instruments and devices with long, narrow, inaccessible orifices such as those found on flexible endoscopes as well as the inner surfaces of take-apart, modular instruments. In the case of sophisticated instruments which may no longer be able to be taken apart in the future, adequate cleaning performance must also be achieved.
A variety of cleaning machines and related apparatus have been developed for medical instruments and devices.
U.S. Pat. No. 3,640,295 to Peterson describes an ultrasonic cleaner and surgical instrument carrying case, which is useable separately and apart from or in combination with the ultrasonic cleaner, the ultrasonic cleaner including within at least one sink and oscillatable cradle which may carry the instrument case during the ultrasonic cleaning process. A pump and filter are additionally provided as part of the ultrasonic cleaner to circulate a cleaning fluid within the sink of the ultrasonic cleaner and to remove particles and other matter from the fluid. The Peterson '295 patent does not address standards or quality of cleaning.
U.S. Pat. No. 3,957,252 to Storz and assigned to Storz-Endoskop GmbH discloses an apparatus for cleaning medical instruments. The apparatus disclosed in the '252 Storz patent pertains to support means provided for mounting an ultrasonic oscillator for engaging washing water in a conventional sink, for use in cleaning medical instruments. The focus of the invention is to eliminate the need for an independent special ultrasonic cleaning tank.
U.S. Pat. No. 4,064,886 to Heckele and assigned to Riwoplan Medizin-Technische Einrichtungs-Gesellschaft GmbH discloses an apparatus for cleaning endoscopes, comprising a holder device, a cylindrical cleaning container, time control means for placing the holder device under timed control and a rotatable mounting for the holder device. The object of the invention is to enable fast and automatic cleansing and sterilization of endoscopes, which can be carried out without damaging the endoscopes. Again, the invention does not address standards or quality of cleaning.
U.S. Pat. No. 4,710,233 to Hohmann et al. and assigned Siemens Aktiengesellschaft discloses a method and apparatus for cleaning, disinfecting, and sterilizing medical instruments with a sequence of method steps performed in a single apparatus. The invention discloses a complicated method and apparatus. The method steps include precleaning the instruments in a container containing a first fluid bath subjected to ultrasonic energy for a period of time T1, subsequently emptying the first fluid bath from the container and replacing it with a second fluid bath containing a cleaning agent and sodium chloride, fine cleaning and disinfecting the instruments by subjecting the second bath to ultrasonic energy for a time period T2 and circulating the second bath through an electrolytic cell having a voltage applied to the electrodes to create an electrolytic disassociation therein, then emptying the second bath and replacing it with a rinse bath, rinsing instruments for a time period T3 by subjecting the rinsing bath to ultrasonic energy and circulating the rinsing bath through the electrolytic cell subsequently emptying the rinse bath, and drying the instruments by means of heated air. Thus, the Hohmann '233 invention is designed to provide adequate cleaning and sterilization of medical instruments, however, this is achieved with an expensive and complicated apparatus and method.
U.S. Pat. No. 5,032,186 to Childers, et al. and assigned to American Sterilizer Company discloses a method and apparatus for washing and sterilizing hospital or laboratory materials. The invention involves loading a chamber with items to be washed, filling the chamber to a predetermined level with a washing fluid, controllably injecting a steam or an air-steam mixture into the chamber during the filling of a chamber with the washing fluid, the steam being injected in a turbulent manner to create a washing action and to begin heating the washing fluid, and continually injecting steam into the chamber after the chamber is filled to the predetermined level so as to subject the items to a washing action. After the washing phase, the chamber is drained, the items are rinsed and the chamber is drained again. Sensors are employed to monitor the operating parameters of the apparatus. Sensors are utilized for controlling the operation of the spray nozzles and the steam injectors such that steam is controllably injected into the chamber after a certain point during the filling of the chamber with the washing fluid to create a washing action and to begin heating the washing fluid. Again, this invention does not provide means to assure adequacy of cleaning.
U.K. Patent Application No. 2,248,188 A to Parker, et al. and assigned to Keymed Ltd. discloses a method and apparatus for cleaning and disinfecting medical instruments. The method and apparatus of the invention are particularly suited for cleaning and disinfecting endoscopes. The method comprises the steps of placing an instrument in an enclosure and subjecting the instrument to a cleaning phase in which a cleansing solution is applied to the surfaces of the instruments, a disinfection phase in which a disinfectant solution is applied to the surfaces of the instrument, a rinsing phase in which a flushing solution is applied to the surfaces of the instrument, a purging phase in which a volatile liquid is applied to the surfaces of the instruments and a drying phase in which a drying gas is passed over the surfaces of the instrument. The cleaning phase is described as a period sufficient to thoroughly clean the endoscope both externally and internally. Again, the invention does not address means for assuring adequacy of cleaning.
None of the aforementioned apparatus and methods provide the means for assuring adequacy of cleaning of a medical device or instrument. Therefore, a need remains for an improved apparatus and method for monitoring cleaning processes for medical devices.